Method and apparatus for manufacturing roll-reduced stranded cable



Oct. 25, 1966 J. GILMORE 3,280,544

W. METHOD AND APPARATUS FOR MANUFACTURING ROLL-REDUCED STRANDED CABLEFiled NOV. 15, 1963 INVENTOR William J. Gilmore ATTORNEYS United StatesPatent 3,280,544 METHOD AND APPARATUS FOR MANUFACTUR- ING ROLL-REDUCEDSTRANDED CABLE William J. Gilmore, Manitou Beach, Mich., assignor toAmerican Chain & Cable Company, Inc., New York,

N.Y., a corporation of New York Filed Nov. 15, 1963, Ser. No. 324,028 3Claims. '(Cl. 576) This invention relates to the manufacture ofcompacted stranded cable and, more particularly, to an improvedapparatus and method for simultaneously roll-reducing stranded wiresradially while pulling them from a strander head through a closing die.

Stranded cable, which may comprise one or more layers of helicallydisposed wires about a core wire, is often compacted radially so thatthe voids between the wires are substantially closed and the exposedcrown portions on the exterior wires are flattened to a con siderableextent. One purpose in compacting stranded cable is to achieve thehighest ratio of tensile strength to cross sectional size and another isto smooth out the otherwise ridged surface of the strand presented byits exterior wire-s. Compacted cable finds particular application asaircraft tow target line, electrical transmission core wire strands, andstrands for large sizes of wire rope.

The conventional approach to the problem of compacting stranded cablehas been to associate swaging dies, reducing rolls of the idling type,or draw dies with otherwise conventional rotary stranding equipment. Theswage-r, idling rolls, or draw die, is located between the positivelydriven haul-off capstan and the closing die in which the individualwires are brought together from their spools on the strander head. Afterthe haul-off capstan pulls the wires through the closing die to form thestrand, the strand is continuously compacted and thereafter is directedto the take-up reel. It is the primary purpose of the present inventionto improve on such apparatus by eliminating certain parts thereof,reducing the operating and maintenance costs, and achieving a superiorcompacted stranded product.

Broadly stated, the invention is directed to stranding apparatus whereinwires on a rotatable head are brought together in a closing die on theaxis of rotation of the head and wrapped helically to form a strand. Theimprovement comprises at least one pair of opposed strand reducing rollson the outlet side of the closing die for compacting the strandradially, and drive means for positively rotating the reducing rolls toprovide the sole tractive force for pulling the wires from the headthrough the closing die. The invention is also directed to the method ofmaking stranded cable wherein wires are directed through and wrappedtogether helically in a closing zone to form a strand. In such a method,the improvement comprises applying radial compacting forces to at leastone portion of the strand at a station on the outlet side of the closingzone, and simultaneously applying longitudinal tractive forces to thestrand portion at the station to pull the wires through the closingzone.

The aforementioned objects of the invention are achieved by eliminatingthe separate haul-off capstan which heretofore was relied upon even whenradial compacting means were incorporated into the stranding apparatus.In accordance with the invention, positively driven reducing rol-lsserve to squeeze the wires of the strands together and at the same timeto pull the wires through the closing zone. The initial expense andmaintenance costs of a separate driven capstan are thus avoided. Also,all the wires of the strand are subjected to substantially the sameelongating and compacting forces as they pass through the drivenreducing rolls of the invention and there is no looseness of any wiresof the resulting product, as there often is when a conventional capstanpulls the strand through a separate swager, idling rolls or draw die.

A preferred embodiment of the invention is described hereinbelow withreference to the accompanying drawing showing an elevation of theapparatus in schematic form.

, A rotary strander head indicated generally by the numeral 10 is drivenby gears 11 through a shaft 12 from a motor 13. The strander head 10 maybe of the conventional planetary type wherein a plurality of spools 15are mounted in a manner well known in the art. These spools carryrespective wires 16 which are drawn therefrom in the usual manner as thestrander head 10 rotates and are brought together in a convergingfashion at an annular closing die 17 disposed on the axis of rotation ofthe head 10. A spool 18 directs a core wire 19 through the center of thestrander head 10 so that the wires 16 are helically wrapped together inthe closing die 17 about the core wire 19. A plurality of layers of thewire 16 may be wrapped one over the other in the closing die 17 in aconventional manner, and a strand 20 is thus formed which proceeds fromthe outlet side of the closing die.

As mentioned previously, the conventional practice is to pull the strand20 from the closing die 17 by means of a haul-off capstan and to subjectthe strand to separate radial compacting means at some point before itreaches its take-up reel. The present invention improves upon suchprocedures by locating a positively driven strandreducing roll unit 21between the closing die 17 and a take-up roll 22. The unit 21 not onlycompacts the strand 20 but also provides the sole tractive force forpulling the wires 16 and 19 from the head 10 and through the closing die17.

The unit 21 advantageously consists of an even number (eight in thisembodiment) of pairs of opposed strandreducing rolls 25 adjacent theoutlet end of the closing die 17. Each roll is formed with acircumferential groove conforming to the desired half cross section ofthe compacted strand 20. Every other pair of rolls is disposed in aplane perpendicular to that of the adjacent pairs thereof to subject thestrand 20 to circumferentially uniform' compacting forces.

Transmission means for rotating each pair of rolls 25 is driven by themotor 13, which also is the driving means for the strander head 1 Thus,as shown schematically in the drawing, gears 26 may transmit rotarymotion from the shaft 12 to the rolls in the unit 21. The transmissionmeans inoludes one positive infinitely variable speed changing device 27between the gears 26 and the unit 21. By adjusting the speed changingdevice 27, the speed of all the pairs of rolls 25 is varied with respectto the speed of the strander head 10, so that variations in the lay ofthe wires .16 in .the strand 20 can be achieved. The transmission meansalso includes a slip clutch 28 on each roll of each pair 25 thereofwhich governs the tractive force imparted to the strand 20. The take-upreel 22 about which the strand 20 is wrapped is of the conventional typeand may be driven by any suitable means.

It should be emphasized that the value of this new strand compactingtechnique is not merely that it eliminates the haul-olf capstanheretofore considered indispensable, though that is a significantbenefit. A feature which is perhaps even more significant is that eachwire is squeezed and pulled simultaneously to a uniform extent andconsequently there is no evidence in the finished strand of anylooseness in the wires. In the prior art practices on the other hand,the wires of the strand are compacted either before or after they aresubjected to the pull of the capstan and the incidence of looseness isappreciable. Hence, there is little or no constructional Patented Oct.25, 1966 st-retc when the strand '20 is put to use under a tensile loadbecause it includes no relatively tight wires which would elongate underan initially disproportionate share of the load.

I claim:

'1. In stranding apparatus wherein wires are withdrawn from respectivespools revolvable about the axis of and mounted on a head which isrotatable by driving means, said wires being brought together about acore wire in a closing die on said axis and wrapped helically to form astrand of a plurality of layers, the improvement which comprises an evennumber of pairs of opposed grooved strand reducing rolls adjacent theoutlet end of said closing die for compacting the strand radially, everyother one of said pairs of rolls being disposed in a plane perpendicularto that of the adjacent pairs thereof, and transmission means driven bysaid driving means for positively rotating each pair of reducing rollsto supply the sole tractive force for pulling said wires from said headthrough said closing die, said transmission means including one positiveinfinitely variable speed changing means for all of said pairs of rollsand slip clutch means for each respective pair of rolls.

2. In a method of making stranded cable wherein wires are directedthrough and wrapped together helically in a closing zone to form astrand, the improvement which comprises applying radial compactingforces to opposite sides of at least two portions of said strand at astation on the outlet side of said closing zone, the angular directionin which the radial compacting forces are generally applied beingdifferent at the various strand portions, and simultaneously applyinglongitudinal tractive forces to all of the wires of the strand in eachof said portions thereof at said station to pull said wires through saidclosing zone.

3. In a method of making stranded cable wherein wires are directedthrough and wrapped together helically about a core wirein a closingzone to form a strand, the improvement which comprises applyingdistributed radial compacting forces equally to opposite sides of aplurality of portions of said strand .at a station on the outlet side ofsaid closing zone, the angular direction in which the radial compactingforces are generally applied being displaced at right angles from one ofsaid strand portions to the next, and simultaneously applyinglongitudinal tractive forces substantially uniformly to all of the wiresof the strand in each of said portions thereof at said station to pullsaid wires through said closing zone.

References Cited by the Examiner UNITED STATES PATENTS 1,742,172 12/1929Atwood 57138 X 1,947,775 2/1934 Hill 571'38 X 2,079,873 5/1937 Reed 57-92,503,987 4/1950 Anderson 57138 FRA'NK J. COHEN, Primary Examiner.

MERVI'N STEIN, Examiner.

D. E. WATKINS, Assistant Examiner.

1. IN STRANDING APPARATUS WIRES ARE WITHDRAWN FROM RESPECTIVE SPOOLREVOLVABLE ABOUT THE AXIS OF AND MOUNTED ON A HEAD WHICH IS ROTATABLE BYDRIVING MEANS, SAID WIRES BEING BROUGHT TOGETHER ABOUT A CORE WIRE IN ACLOSING DIE ON SAID AXIS AND WRAPPED HELICALLY TO FROM A STRAND OF APLURALITY OF LAYERS, THE IMPROVEMENT WHICH COMPRISES AN EVEN NUMBER OFPAIRS OF OPPOSED GROOVED STRAND-REDUCING ROLLS ADJACENT THE OUTLET ENDOF SAID CLOSING DIE FOR COMPACTING THE STRAND RADIALLY, EVERY OTHER ONEOF SAID PAIRS OF ROLLS BEING DISPOSED IN A PLANE PERPENDICULAR TO THATOF THE ADJACENT PAIRS THEROF, AND TRANSMISSION MEANS DRIVEN BY SAIDDRIVING MEANS FOR POSITIVELY ROTATING EACH PAIR OF REDUCING ROLLS TOSUPPLY THE SOLE TRACTIVE FORCE FOR PULLING SAID WIRES FROM SAID HEADTHROUGH SAID CLOSING DIE, SAID TRANSMISSION MEANS INCLUDING ONE POSITIVEINFINITELY VARIABLE SPEED CHANGING MEANS FOR ALL OF SAID PAIRS OF ROLLAND SLIP CLUTCH MEANS FOR EACH RESPECTIVE PAIR OF ROLL.